Whether traveling in a strange land or the state next door, what you don't know can hurt you. Local seat belt ordinances, U-turn policies, and even rules governing cell phone use and texting vary from state to state, as do the legality and distribution of speed cameras, red light cameras and other "gotcha" technologies. Legal sites like FindLaw.com maintain lists of state traffic laws, so study up before you hit the highway. As the saying goes, ignorance of the law is no excuse.
Community sites like The National Speed Trap Exchange list ticket traps for every state, broken down by area and route (as a rule, slow down around hills and blind curves). Some law enforcement agencies receive federal overtime pay for writing tickets in construction zones, which often have higher fines to boot, so avoid them whenever possible. State department of transportation Web sites frequently list construction zones along with road delays, so be sure to check them out. Also, try to avoid driving (and speeding) during holidays or late at night, when drunk driver patrols are heavy. You're more likely to get pulled over.